From 31b23b5d49a6abf4114a5c56ad878ff6eeac145c Mon Sep 17 00:00:00 2001
From: Heiko Bornholdt <heiko@bornholdt.it>
Date: Mon, 4 Nov 2024 00:28:34 +0100
Subject: [PATCH] Fix behavior of TunChannel#isOpen

---
 src/main/java/org/drasyl/channel/tun/TunChannel.java | 12 ++++++++----
 .../drasyl/channel/tun/jna/AbstractTunDevice.java    |  6 ------
 .../java/org/drasyl/channel/tun/jna/TunDevice.java   |  7 -------
 .../channel/tun/jna/darwin/DarwinTunDevice.java      |  1 +
 .../drasyl/channel/tun/jna/linux/LinuxTunDevice.java |  1 +
 .../channel/tun/jna/windows/WindowsTunDevice.java    |  1 +
 6 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/src/main/java/org/drasyl/channel/tun/TunChannel.java b/src/main/java/org/drasyl/channel/tun/TunChannel.java
index 367e023..c2bc1f1 100644
--- a/src/main/java/org/drasyl/channel/tun/TunChannel.java
+++ b/src/main/java/org/drasyl/channel/tun/TunChannel.java
@@ -68,6 +68,7 @@ public class TunChannel extends AbstractChannel {
     private boolean readPending;
     private final EventLoop readLoop = new DefaultEventLoop();
     private TunDevice device;
+    private boolean closed;
 
     public TunChannel() {
         super(null);
@@ -85,12 +86,12 @@ public TunChannelConfig config() {
 
     @Override
     public boolean isOpen() {
-        return device == null || !device.isClosed();
+        return !closed;
     }
 
     @Override
     public boolean isActive() {
-        return device != null && isOpen();
+        return !closed && device != null;
     }
 
     @Override
@@ -128,8 +129,11 @@ protected void doDisconnect() throws Exception {
 
     @Override
     protected void doClose() throws Exception {
-        if (device != null) {
-            device.close();
+        if (!closed) {
+            closed = true;
+            if (device != null) {
+                device.close();
+            }
         }
     }
 
diff --git a/src/main/java/org/drasyl/channel/tun/jna/AbstractTunDevice.java b/src/main/java/org/drasyl/channel/tun/jna/AbstractTunDevice.java
index e6c4907..65b0796 100644
--- a/src/main/java/org/drasyl/channel/tun/jna/AbstractTunDevice.java
+++ b/src/main/java/org/drasyl/channel/tun/jna/AbstractTunDevice.java
@@ -27,7 +27,6 @@
 
 public abstract class AbstractTunDevice implements TunDevice {
     protected final TunAddress localAddress;
-    protected boolean closed;
 
     protected AbstractTunDevice(TunAddress localAddress) {
         this.localAddress = requireNonNull(localAddress);
@@ -37,9 +36,4 @@ protected AbstractTunDevice(TunAddress localAddress) {
     public TunAddress localAddress() {
         return localAddress;
     }
-
-    @Override
-    public boolean isClosed() {
-        return closed;
-    }
 }
diff --git a/src/main/java/org/drasyl/channel/tun/jna/TunDevice.java b/src/main/java/org/drasyl/channel/tun/jna/TunDevice.java
index 6a3ddd5..3f3aece 100644
--- a/src/main/java/org/drasyl/channel/tun/jna/TunDevice.java
+++ b/src/main/java/org/drasyl/channel/tun/jna/TunDevice.java
@@ -56,11 +56,4 @@ public interface TunDevice extends Closeable {
      * @throws IOException if write failed
      */
     void writePacket(final ByteBufAllocator alloc, final TunPacket msg) throws IOException;
-
-    /**
-     * Returns whether the device is closed or not.
-     *
-     * @return {@code true} if the device has been closed.
-     */
-    boolean isClosed();
 }
diff --git a/src/main/java/org/drasyl/channel/tun/jna/darwin/DarwinTunDevice.java b/src/main/java/org/drasyl/channel/tun/jna/darwin/DarwinTunDevice.java
index d9b6912..c7c5559 100644
--- a/src/main/java/org/drasyl/channel/tun/jna/darwin/DarwinTunDevice.java
+++ b/src/main/java/org/drasyl/channel/tun/jna/darwin/DarwinTunDevice.java
@@ -73,6 +73,7 @@ public final class DarwinTunDevice extends AbstractTunDevice {
     }));
     private final int fd;
     private final NativeLong readBytes;
+    protected boolean closed;
 
     private DarwinTunDevice(final int fd, final int mtu, final TunAddress localAddress) {
         super(localAddress);
diff --git a/src/main/java/org/drasyl/channel/tun/jna/linux/LinuxTunDevice.java b/src/main/java/org/drasyl/channel/tun/jna/linux/LinuxTunDevice.java
index db90138..28d265b 100644
--- a/src/main/java/org/drasyl/channel/tun/jna/linux/LinuxTunDevice.java
+++ b/src/main/java/org/drasyl/channel/tun/jna/linux/LinuxTunDevice.java
@@ -59,6 +59,7 @@ public final class LinuxTunDevice extends AbstractTunDevice {
     private static final IllegalArgumentException ILLEGAL_NAME_EXCEPTION = new IllegalArgumentException("Device name must be an ASCII string shorter than 16 characters or null.");
     private final int fd;
     private final NativeLong mtu;
+    protected boolean closed;
 
     private LinuxTunDevice(final int fd, final int mtu, final TunAddress localAddress) {
         super(localAddress);
diff --git a/src/main/java/org/drasyl/channel/tun/jna/windows/WindowsTunDevice.java b/src/main/java/org/drasyl/channel/tun/jna/windows/WindowsTunDevice.java
index cd784bb..b38edef 100644
--- a/src/main/java/org/drasyl/channel/tun/jna/windows/WindowsTunDevice.java
+++ b/src/main/java/org/drasyl/channel/tun/jna/windows/WindowsTunDevice.java
@@ -62,6 +62,7 @@ public final class WindowsTunDevice extends AbstractTunDevice {
     public static final WString TUNNEL_TYPE = new WString("drasyl");
     private final WINTUN_ADAPTER_HANDLE adapter;
     private final WINTUN_SESSION_HANDLE session;
+    protected boolean closed;
 
     private WindowsTunDevice(final WINTUN_ADAPTER_HANDLE adapter,
                              final WINTUN_SESSION_HANDLE session,